Aircraft



H. H. PLATT- March 10, 1931.

AIRCRAFT Filed Dec. 30, 1927 6 Sheets-Sheet l I INVENTOR: HIV/Z fiA/D hf PL 1777;

" U ATTORNEYS.

March 10, 1931. I H. H. PLATT 1,795,501

AIRCRAFT Filed Dec. 30, 1927 e Sheets-Sheet a 550 now on LIA/E. 6-6.

u U ATTORNEYS.)

H. H. PLATT AIRCRAFT March 10, 1931.

R 0 TI N E V N H. H. PLATT AIRCRAFT 1 March 10, 1931.

6 Sheets-Sheet 5 Filed Dec. 50, 1927 H. H. PLATT March-10, 1931.

AIRCRAFT Filed Dec. 30, 1927 6 Sheets-Sheet 6 Dn O T N E V N lzlivougle its orbit Wit i each TGVOllltlOll of the till lit!

of Fi voter, in ocdei: thot eoch oi" the number of domicile comprising the rotor may be preouted to the air at their various positwns in their orbit, (Ll? successively vorying onpglee neccssery in order for eoclo. oerofoil to perform the i'fimction ofi propulsion end the function of lift, respectively,

(3) The provision oi moons within the oivci'oft tor vmrying and controlling, et the will oi the opeiotov the direction 021' the 'tlemist thus produced my the rotor.

ll Moons; for 'vovyinp; and controlling, ot the will of the operator, the megnitude of the thrust thus produced,

(5) The provioion 2. pair of such rotors, one on eocli side of the machine, endmeons for citizen jointly or inde ndently and. coottolling both the dnrection ct pvopulsion or angle tlomiet, as Well the mogultude of such pif opuleion 011 thrust each of the two iflilfllffi, theceby to ottcin loteml novigability no towing, banking and the like. 1

In the occomponying drovvinge, I loeve illustrated in o. general woy, o. form of conctvuction embodying the above structural and functional chovectoristics, oltliou in Without any attempt to show any detoilc constructicn.

Thus, Figure 1 represents a. top plon view of on aircraft of my novel construction showtlie l'ruseloge, portly in section and chowing the pair oi? tcensvorsely disposed rotors (one pomly broken away).

Figure 2 represents o. side elevation oil on oircraft of this construction, illustrating Eurtlier the geneml i'elotion oi the voter to tlic filfifllfl'ge Figure 3 represents c section on line 3-3 ofi Figure 2 (with one of the rotors not shown.)

illimoting the method of driving the prooel lot or rotor and the method of centre ing; the angle end magnitude oi the tluvuet on the voice, item within the fuseloge.

Figure d represents o. povtiol eide elevetion, on cn'enleoged scale, oithe covet-oil or Mode deflecting ems oi the rotor and the driving and cont olling moons within therotor. V

Figure 5;). race to 'e eection ouline 5-5 re 4, il u'stmtiug generally the method of. dnving or propellin and the method of actuating the la e de ectingi arms ondelso the manner of varying or conti'ollin the movements of the deflecting arms, there y to control the angle and magnitude of the resultant thrust of the rotor as it whole.

Figure 6 represents 2. section on line 66 of Figure 3, on an enlarged scole, illustrating the means Within the fuselage for controlling the angle as Well as the magnitude of the thrust oi each of the two rotors either jointly or independently of each other.

Figure 7 represents c section on line 7- of Figure 6.

Figures 8 to 13 inclusive represent diogi'ommotic views of illustrating the angles of the several bledcs oi ocrofoils of the rotor for the various conditions of flight or ncvigation, end the respective settings or positions of the manual controls Within the fuselage, for obtaining these blode angles.

Accordingly, Figure 8 is o. diagram 0 rotor and controls in the straight or full.-

speed-ahead position, under power.

Figure 9 represents a similar diagram of rotor and controls for vertical ascent or descent or hovering, under power. I

Figure 10 represents a. similar diagram of rotor endcontrols in a. position intermediate to that shown in Figures 8 and 9, for on inclined ascent under power.

Figure 11 represents & mimilcr diagram of rotorund controls with the direction of pro pulsion or engle of thrust shifted into a. rear word reverse direction or opposed to the direction of travel, for decelerating the chine.

Figure 12 represents zit-similar diagram of rotor and controls showing the some in :1. position for vertical descent, without power, and with the rotors free to revolve.

Figure 13 represents a similar diagram of rotor and controls with the angle of thrust directed downwardly for running the engine under load on the ground, for the purpose of warming the engine.

ln Figures 1, 2 and 3 of the accompanying drawings, the fuselage of the air credit of my novel construction is designated generally by the numeral 15. The fuselage may be of any suitable shape and construction, os moy be required by the necessary strength, the Wind resistance, and gmvity forces.

lt Will be noted that the aircraft of novel construction locks the fixed. lifting sun feces or whatere commonly termed Wings, which invu 'icoly form an indispensclile port oi the conventionol aircraft now in'uco, 'itulikevvise locks the conventional form of propeller.

llnstcod, the oircraftof my novel construction is provided with, what may arbitrarily llli ing drawings, each rotor contains four blades I or aerofoils; that number having been found to give satisfactory results. For some purposes rotors of three blades as well as pos-v sibly five and six blades, may also be desirable.

The two rotors 16 and 17 are supported and driven by a common axial horizontal shaft 19 extending transversely through the fuselage and may be suitably journalled in a central bearing 20 as well as in a pair of opposed terminal bearings 21, carried by and preferably forming part of a driving shaftand gear housing 22, near the top of the fuselage.

The shaft and gear housing 22, being rigid with the fuselage 15, projects outwardly from each side of the fuselage, as seen particularly in Figures 1 and 3, in gradually tapering" form, so as to give the driving shaft 19 the necessary rigid support near the point of the load, to wit,near the outer extremities thereof.

The opposed ends of the main driving shaft 19 extend through the bearings 21, in each end of the laterally projecting shaft and gear housing 22, and also extend through a bearing sleeve 23, which is formed integrally with, or built rigidly with the housing structure 22 and bearings 21.

To each end of the shaft 19, immediately adjacent to the bearing sleeves 23, suitable flanges 24 are fixedly secured. A driving arm spider 25 is provided at the end of the main driving shaft 19, having a hub 26 and a number of similar radial driving arms 27, extending to the number of blades comprising" the rotor. A shaft extension 28, having a corresponding flange 29 is secured to each of the opposed ends of the main shaft 19 as Well as to the corresponding driving arm spider 25, by means of a series of bolts 30 extending through the two flanges 24 and 29, onthe main shaft 19 and shaft extensions 28, respectively, and extending also through the hub 26 of the arm spider 25.

Each of the blades 18 is pivotally secured to the corresponding driving arm27, at a point substantially midway of its length,

andwith the axis of the pivot being substantially at the center of gravity of the crosssection of the blade, which latter depends upon the particular cross-section of the blade.

The blades 18 may be of any suitable internal construction, although preferably formed of metal. Thus the blades 18 are preferably thin-Walled, metallic shells, hollow within, except for bracing Webs of metal to give it the necessary rigidity and strength,

and are preferably formed of some of the well-known aluminum alloys. The method of pivoting the blade 18 to the driving arm 27 (as well as other supporting and deflecting arms to be described hereinafter) is not shown in detail in the accompanying drawings, and any suitable pivot construction may be employed for the purpose.

In order to give each blade 18 the necessary resistance to centrifugal forces, whilethe rotor is in motion, and in order to give the rotors 16 and 17 as a whole, the necessary rigidity, the blades 18 are further supported at or near their opposed ends, by corresponding arms 31 and 32, respectively, to which the blades are similarly pivotally secured at the center of gravity of their cross-sections and in axial alignment with the pivotal support of the main driving arms 27. 7

Each set of supporting arms 31 is formed integral with, and is carried by a common annular hub or ring 33 which loosely sur rounds the corresponding tapering shaft and gear housing 22.

The outer supporting arms 32, on the other hand, are also preferably formed integral with a central hub 34, which is secured to a terminal flange 35 on the outer ends of the shaft extensions 28, by means of bolts 36.

By this means, each blade is supported at its center of gravity against the centrifugal force, as well as against air pressure, at three points along its entire length, while the driving-support, through the arms .27, is

positioned substantially midway of its length.

As pointed out hereinabove, the rotors, consisting of a plurality of pivotally mounted aerofoils or blades perform two separate and distinct primary functions; one is the propeller function and the other is the wing or lift function. To perform these two functions the rotor or more particularly each blade of the rotor, must be presented to the air stream at various angles as it travels around in a substantially circular path about the axis of the shaft 19.

The arrow 37 in Figures 2 and 8 to 13 inelusive indicate the direction of rotation of the rotor, as well as the path of the blades comprising the same.

in order to vary the angle of each blade at different parts of its. travel in the circular path, each blade is connected to a. common, normally stationary eccentric, by means of an eccentric strap 38 and a deflecting rod 39, which is rigid and preferably integral with the eccentric strap and the free end of which is pivotally secured to the blade 18 in advance of the supporting pivot, preferably near the leading edge thereof.

By this means, each blade is deflected in succession, between two opposed extreme limiting angular positions, as it passes ill 4 master.

through each revolution or as it travels through the circular orbit of the blades. The positions in the circle, of the two limitin angles of the blades in their circular or it, is determined by the direction of the eccentricity of the eccentric, while the magnitude of deflection of the blades, either from their median position or between their two extreme positions, is determined by the amount of the eccentricity.

The direction of the eccentricity therefore determines generally the direction of the forces produced by the action of the blades upon the air stream, while the amount the eccentricity determines generally the magnitude of the forces so produced.

In order to vary the direction and. the amount or magnitude of the eccentricity, and thus to obtain the necessary navigability of the craft, the eccentric straps 38, instead. of being merely supported upon a normally stationary eccentric, are instead supported or carried by a dual eccentric, both constituent eccentrics of which are normally stationary but movable with respect to the fuselage as Well as with respect to each other, for adjustment or control purposes.

Thus, upon referring particularly to Fig- "ures 3, 4 and 5, it will be noted that the ccto centric straps 38 are rotatably mounted upon an outer eccentric 40, which in turn 'is rotatably mounted upon an inner eccentric 41. The inner eccentric 4:1 in turn is rotatably mounted upon the concentric bearing sleeve 23 which is rigidly afiixed to, or is integral with the shaft and gear housing 22 and terminal main bearing 21.

The inner eccentric dlis integral with, or is rigidly and fixedly secured to a sleeve 42, to the opposed end of which. a inion 43 is fixedly secured. A pinion 44 is rotatably mounted upon the sleeve 42, and carries a flange 45. The flange 45 is provided with a generally radial slot 46 which engages a laterally extending pin or projection ll fixed in the outer eccentric l0. By this means, the outer eccentric may be revolved in either direction for adjustment or control purposes, by merely revolving the concentric pinion 44; the motion between the concentric pinion 4A- and flange or disc the eccentric a0 and eccentric pin 45, being effected by the engagement between the slot 45:6 and the pin 4:7.

The inner eccentric on the other hand, may he revolved in c er direction for adjustment or control purposes, by merely rcroiring the concentric. pinion Inorder to maintai the two eccentri 0 and a l in any desired relative position respect to the fuselage and with respe. each other, a pair of concentric control 31 and 49 are provided on each side or ge, corresponding to each of the Lt l'l'. 'eurnalled within the outer tubular control.

The inner control shafts are shafts a8, while the latter are journallecl in suitable bearings 50 in the fuselage, or more particularly in the main shaft housing 22. Each of the pair of inner control shafts extends beyond the outer tubular control shafts l8 at each end. To the outer ends oi? each of the inner control shafts L9, pinions 51 are fixedly secured, which are constantly in mesh with the pinions 4a which actuate the outer eccentrics 40. To the inner ends of each or? the inner control shafts as, sprocket wheels are secured, over which the sprocket chains pass.

To the outer ends of each of the tubular control shafts 428, similar pinions a e edly secured, which are constantly in with the pinions 4:3, by means 01": which inner eccentrics ll are controlled. The inner ends of each of the outer tubular control shafts in turn carry corresponding sprocket wheels 55, over which the corresponding sprocket chains 56 pass.

The opposed pairs of sprocket-chains 53 and 56 extend downwardly to the pilots or navigators compartment where they pass around the corresponding sprocket wheels 57 and 58, respectively, forming part of the control mechanism within the pilots compartment of the fuselage.

The pilots control mechanism is shown in detail particularly in Figures 3, 6 and 7, while the corresponding control mechanisms in the rotors are illustrated in detail particularly in Figures 3, 4 and 5.

Each of the pair of opposed sprocket wheels 57 is carried by a tubular shaft 59 journalled in corresponding and similar bearings 60 which are rigidly carried upon brackets (51 fixed to the fuselage. To the inner and 'uxtaposed ends of the pair of tubular sha s 59, a corresponding pair of bevelled gears or bevelled gear sectors 62 are fixedly secured in a manner shown particularly in Figure 7. A differential bracket 63 is journalled or rotatably mounted upon one of the tubular shafts 59, by means of the bearing 64.- thereof. A lower and right angular hearing 65 of the differential bracket 63 in turn carries the differential or steering shaft 66, to the inner end of which a bevelled pinion 67 is fixedly secured, which in turn is in mesh with each of the two juxtaposed bevelled gear sectors 62, there y differentially interconnecting the same at L times. The outer end of the shaft 66 carries vheel other handle member 68 the differential or steer g he bracket -63, in either dicutcd in Figure (l, .ch of the two rotor 'uselage, will be revolv iwo opposed directions. to or extent. @n the other the wheel or handle mem- "V5, in either direction .25 igure 3) the outer cc- 1ion. o

eccentii either side oi: m in either the some i 71 or t liltl centric of each of the two rotors, will be deflected or dis laced in 0 posed directions. Thus, by the eflection oi the shaft 66 in either directions 69 and 70 or the rotation of said shaft 66 in either directions 71 or 72, a uniform or a difierential adjustment or control of the outer eccentrics 40 in the rotors 16 and 17 is obtainable.

Each of the sprocket wheels 58, on the other hand, is carried by corresponding shafts 73 which extend through the hollow tubular shafts 59 and project beyond the same at each end. To the inner end of the two shafts 73, lever arms 74 and 7'5 respectively, are secured, which carry arcuate extensions 7 6 and 77, to which corresponding handles 7 8 and 79 are secured. The arcuate extensions 76 and 77 are parallel to each other and are arranged frictionally or positively to interlock with each other at will.

This friction or positive interlocking means may be any suitable detent, catch or the like, which is not shown in the drawings. An arcuate sector 80 is rigidly carried by the bearing 65 of the bracket 63, and arallel to the arcuate leverextensions 76 and 7. Suitable frictional or positive interlocking means are also provided between either one of the arcuate lever extensions 76 and 77 (or both) and the sector 80, which is stationary with respect to the differential bracket 63, whereby either oneor both of the levers 74 and 7 5 and hence the corresponding pair of shafts 73 may be interlocked with the differential bracket 63 and hence interlocked with the pair of tubular shafts 59, in any desired position intermediate of suitable limits.

By such an interlocking of either-one or both of the lever handles .8 and. 79 and the levers 74 and 75 with the difierential bracket 63, either one or both of the corresponding inner eccentrics 41"- in the two rotors respectively, may be revolved or controlled in uni son with the outer eccentrics 40.

The operation The operation of the aircraft, or more par:- ticularly, the control and navigation thereof can best be understood upon a further reference to Figures 8 to 13 inclusive. In these figures the rotor and controls within the fuselage are represented diagrammatically;

In Figure 8, one ofthe eccentric straps 38,

and the deflecting arm 39 are shown while in Figures 9 to 13 inclusive the defiecting arms 39 are merely represented by dotted lines. In these figures the inner and outer eccentrics are represented by corresponding circles designated as 41 and 40 respectively. The fixed or driving center of therotor, that is, the axial center of the driving shaft 19 and bearing sleeve 23, .is represented by the intersection of vertical and horizontal reference lines, represented as dot and dash lines. The dotted circle 44 in each of these diagrammatic figures represents the pinions 43 and 44, concentric with the main driving shaft 19 and bearing sleeve 23, while the dotted circle 51 in these figures represents the pinions 51 and 54, by means of which the former pinions are driven for purposes of eccentric control. The dotted line 56 represents the sprocket chains 53 and 56, while the solid circle 58 represents the two sprocket wheels '58 and 57 within the fuselage. The manual extending from the fixed center to the center of the eccentric circle 41, represents the eccentricity of the inner eccentric, while the light line extendin from the center of the inner eccentric circ e 41 to the center of the outer eccentric 40 represents the eccentricity of the outer eccentric.

It will be observed here, that while the supportin centers 81 of the blade 18, which are pivota y secured to the driving arms 27 and bracing orsupporting arms 31 and 32, revolve in a true andfixed circle about the fixed center (at the intersection of the two dot and dash reference lines), so too, every other part of the blade 18 likewise revolves about a true circle, though eccentric with the first circle. The center of rotation of each of the various parts of the blade 18 is determined by the resultant or effective or total eccentricity of the inner and outer eccentric. The circle 82 in each of these diagrammatic figures represents the path of travel of the pivotal supporting centers of center of gravity of the cross-section of the blade), while the circles 83 represent the path of travel of the deflecting pivot 84 of the blade 18, and hence re resent generally the path of. travel of the eading edge of said blade.

While the circle 82 is fixed, and has its center at the center of the drivin shaft 19, the circle 83 may be varied at wil by means of the eccentric control.

The arrow 85 represents the direction of rotation of the rotor, while the arrow 86. represents the forward direction of the aircraft.

As pointed out heretofore, the magnitude of the force produced by the rotor is determined b the maximum deflection or angularity o the blade angle during each revolution, which in turn is determined by the amount or magnitude of the eccentricity. This is indicated in the diagrammatic views, by the distance between the fixed center (intersection of the two dot and dash reference lines) and the center of the outer eccentric 105 the blade (which is at approximately the v till til

.npont e firclf 40 (the free end of the light eccentric As also brought out hereinabove, the direction of the force'produced by the rotor is determined, on the other hand, by the relntive point in the circular path of the blades et which they are deflected to their maximum deflection as determined by the direction or lie of the resultant or efiective eccentricity. This letter is indiceted in the diugremrnatic views by the irneginsry line which passes through the fixed center end the center of the outer eccentric circle ell).

normal condition, fli ht in direction-i, either horizontally, st :ht sway, or on on upward ascending incline, or

verticcl rise, is efc'ecmd by unit ting of both rotors. The unequal setting of the two rotors is required only under one of three conditions; one is to halence the sircrsft when it becomes nccessery to do so for any reason whatsoever, that is, when it is necessary to exert unequal forces on the two sides of the aircraft in order to maintain it on an even keel; second, to change the direction of flight or to turn, and to bank the aircraft simultaneously; and third, to eifect e di lacement of the aircraft sideways.

e navigation of the aircraft under these last three conditions, by an unequclm'tting of the two rotors, will be discussed hereineft er. Thus the reference to the diugrnninietic views of Fi res 8 to 13 inclusive, is mode rimarily with respect to on equal or uniorln settin of the two rotors for flight solely in streig t lines.

Figure 8 the rotor and controls ere shown in a. position for full speed ahead. For full speed ahead, at e uniform altitude, the angle of the effective eccentricity or the direction of thrust of the rotor is inclined upwardly above the horizontal, just suiticiently to maintain the craft at uniform ultitude. This depends upon the loading of the setcraft and upon the forward speed. The oil-- gle or maximum deflection of the blade 18 in turn is so adjusted as to present the blade at the most eficient angle of attack with respect to the relative air stream. This megnitude of the eccentricity or of the rotor thrust, depends among others, also upon the loadin and u a engine power, as Welles .0 of the aircraft.

It shoul be observed here that each blade performs the two distinct functions of ropulsion and lift, generally at two di erent arts of its nth of travel in a circle.

us, when t e blade is at the upper port of the circular orbit it exerts a propelling force, while when the blade is at the lower part of its circular orbit and travels in the same direction as the fuselage, it exerts a lifting force. The lifting force thus produced by the blade is greatly in excess of the lifting force that would ordinarily be produced.

menisci direction as the fuselage and the speed relsw tive to the fuselage is as great or greater than the air speed of the fuselage, and hence the resultant air speed of the blade in the lower part of its circular orbit is double the speed, or more, of the air speed of the TC'USQ- loge.

For this reeson, the aircraft of this con struction can be maintained cleft with seroieil surfaces of an nggregutc projected t less then the fined area required to li sunie weight at the some s l After the heen set with respect to each other b leclr ing the two levers 74 and 75 to the dlfi'erential brschet 63, in thedesired position, end thereby setting the magnitude of the eccentricity, with the condition of flight as shove outlined and indicated in Figure 8, the ultitude of the aircraft may be raised or lowered at will, by merely changing the en is of thrust to the desired degree in the esired direction, without however, necessarily changing the magnitude of the thrust or the magnitude of eccentricity.

'Thus, while the craft is in streight-ewey flight full-speed-ehead, the craft can be put into an inclined ascent or descent, primarily by raising or lowering the angle of the resultent or efiective eccentricity. This is eccoinplished merely by deflecting upwardly or downwardly, in either of the directions indi cuted by the arrows 70 and 69, re pectively, (Figure 8 and Figure 6) the differential shaft 66, us well as the differential bracket 63, without, however, turning the wheel 68.

Thus it will be observed that the raising of the shaft 66 in the direction of the arrow 70, will reise the angle of the total or effective eccentricity by revolving the two eccentrics 40 and 41 in the some direction and to the some extent, thereby retaining the megntiude of the resultant eccentricity unchanged. By deflecting the shaft 66 downwardly in the direction ofthe arrow 69, the reverse tehes place. ill and 40 respectively, are both revolved in a counter-direction to the same degree, thereby lowering the angle of eccentricity, without, however, changing the magnitude thereof.

The dingrum of Figure 9 re resents generolly the condition of flight or: the croft in s straight vertical ascent. It will be oh served that to attain this condition of flight,

the direction of the resultant eccentricity or the direct on of thrust is made Sllllslm .v vertical in on upward dire tion by the operating shaft 66 the direction of to urrow 70 to the desired e "2 recent is Since the of vcrticel Thus the inner and outer eccentrics lll cl Mill lid

sarily considerably less than the forward speed of the craft, it is necessary, for the best efficiency. .to reduce the blade angle or the magnitude of the resultant or effective eccentricity. Thus for "vertical ascent, in addition to deflecting the operating or control.

those shown in Figures 8 and 9, respectively.

Thus the direction of the resultant or eifective eccentricity or the direction of thrust of the rotor is inclined upwardly at an angle greater than that required to maintain the craft at a uniform altitude. To compensate for the reduction of air speed, due to the upward inclined ascent, the magnitude of the eccentricity and hence the angle of the blade is reduced. Accordingly the control shaft 66 is deflected upwardly to a position intermediate of that shown in Figures 8 and 9, while the inner eccentric control handles 7 8 and 7 9 are moved to a position with respect to the control shaft 66 intermediate of the position thereof, shown in Figures 8 and 9, thereby to set the magnitude of the eccentricity to a quantity intermediate of the max-* imum quantity shownin Figure 8, and the lower quantity shown in Figure 9.

In Figure 11 I have shown the method of control of the aircraft when it is desired to decelerate the speed of the craft, let us say, in a forward direction. This feature of the control of the aircraft is analogous to th braking of road vehicles.

This is accomplished by merely changing the angle of the resultant eccentricity or the direction of thrust of the rotor, from a position, for instance, that shown in Figure 8, (full speed ahead) to a position shown in Figure 11, that is, in a somewhat rearward direction or back of vertical. This rearward deflection of the angle of thrust of the rotor must be accompanied, however, by a decrease in the amount of eccentricity or a decrease in the blade angle, which in turn is accomplished by bringing the inner eccentric control handles 7 8 and 79 nearer to the control shaft 66. The effect of this control is to exert a. direct retarding force upon the aircraft, thereby checking its speed. As the speed of the craft is decreased by this operation, the direction of eccentricity or the direction of thrust'is again brought forward towards the vertical, so as to maintain the desired altitude of the craft, notwithstanding the reduction in speed, or possibly notwithstanding the bringing of the craft to a standstill.

It will be seen from the foregoing, that the aircraft is navigable under power either in a straight away flight or an upward or a downward inclined ascent or descent, as well as a vertical ascent or descent, at practically any desired horizontal or vertical speed,

thereby rendering the craft universally controllable under power and capable of landing and taking ofl without any limitations as to size or character of landing field.

It should be observed, however, that the aircraft of this novel construction is not limited in navigation to control under power. It is likewise capable of an inclined or a vertical descent without power, as would be occasioned by failure of the engine. Under such emergency conditions the main driving shaft 19, and hence the rotors 16 and 17 are disconnectedfrom the engine or source of driving power, by means of a clutch 87 (shown only conventionally) which may be operated by any suitable handle 88 in proximity to the pilot quarters. The clutch 87 transmits the power from the bevelled gear 89 to the main driving shaft 19 whichextendstransversely of theaircraft and carriers at its two op osed ends, the two rotors 16 and 17, respectively. The source of ower is represented diagrammatically in igures 1 and 2, as the internal combustion engine 90, suitably connected with the main driving shaft 19, through the bevelled pinion 91.

In order to navigate the craft without power, that is, under emergency condition,.with the source of power90 disconnected from the main driving shaft 19, and with the rotors 16 and 17 therefore free to revolve in unison with each other, a third function of the rotors is utilized. Under this condition of the flight, the rotors are maintained in rotation by the windmill action of the air stream upon the rotors, as the craft passes through the air by the force of gravity. I

Thus, for an inclined or gliding descent without power, the blade angle and the direction of thrust .or the angle of the resultant eccentricity, is set in substantially the position shown in Figure 8 for full speed flight ahead, under power. For a vertical descent without power, on the other hand, the eccentricity is set substantially as shown in Figure 12. Under each of these two conditions of free flight, as well as any intermediate position, the angle of the resultant eccentricity, or what may be termed the normal direction of thrust of the rotor (under power,) is set substantially in line with the direction of travel of the aircraft, or substantially in line with the air stream. The'effect of this is to produce a windmill action upon the rotor, by the air stream, and thereby to maintain the rotor in rotation.

in a free inclined descent the rotors are till maintained in rotary motion by the actionof the air stream upon the blades, when at a certain part of the path of their travel, while the same blades when at a difierent part of their circular path of travel, will be presented to the same air stream at an angle so as to produces reaction opposed to the force of gravity, thereby checking the free downward or vertical component of travel of the aircraft. Here too, the blades in their lower positions act as gliding surfaces.

in a free vertical descent, the blades act as gliding surfaces both in their 1. war and upper positions, that is, when moving of the direction of tr el of the cre it will. be observed t for an ilined free gliding travel, with the aircraft set subs w.- tially in the condition shown in Figure 8, the magnitude of the eccentricity is considerably greater than the magnitude of the eccentricity for a free vertical descent, as shown in Figure 12. It is estimated under either one of these two conditions of the free or gliding flight, either in an inclined or a vertical descent or intermediate angles of descent, the vertical speed of the craft can be kept down to a minimum which will afford a safe landing, while the horizontal speed of the craft can be controlled between any suitable limits and may be reduced to zero, as for instance, in a vertical descent. By this means, therefore, a safe navigability of the craft is obtained even under emergency condition.

In Figure 13, l have illustrated the setting of the rotors and controls when it is desired to warm up the engine in preparation for flight. Thus instead of anchoring the aircraft as is now necessary while warming up the engine, it is merely necessary to deflect the angle of the eccentricity or the direction of thrust in a downward vertical direction, that is, toward the ground. The engine and the rotors may thus be operated indefinitely with the aircraft stationary on the ground.

The foregoing is a general outline of the methods of control, for flights in substantially straight direction.

In order to change the direction of a craft while in flight, that is to turn about, a differential control of the two rotors 16 and 17 is resorted to.

n will beobserved that by deflecting the shaft 66 as well as the handle wheel 68 in "either direction 69or 70, without, however,

Thus, depending. upon the direction of romentor tation of the wheel 68 the angle of the eccentricity of the eccentric 40 in either one of the two rotors 16 and 17 will be deflected upwardly with respect to the angle of eccentricity of the inner eccentric 11, while the same eccentricity in the other rotor will be deflected downwardly to like extent.

By this operation the resultant eccentricity in the two rotors is changed both as to direction and as to magnitude, and hence the thrust of the two rotors 16 and 17 is altered dififerentially both as to direction and magnitude.

will be observed moreover, that by t ferentially one only o two out ecce? straight owe the resultant eo ntricity rotor is rm both as to and as to magnitude, in the other rotor the angle of the eccentricity is lowered and the magnitude is decreased correspondingly, The effect of this is not merely a turning of the craft, due to an unequal thrust exerted by the two rotors, but

.also a simultaneous and automatic banking of the craft due to a raising of the angle of the eccentricity or the ,direction of thrust on the outside of the turn and a lowering of the same on the inside.

The differential control of the inner eccentrics 11, by a diflerential setting of the two inner eccentric handles 7 8 and 79-, is utilized primarily for balancing purposes or for stabilizin the aircraft.

ln igures 2, 3 and 8 to 13 inclusive, the ilots seat is designated generally by the numeral 92, while an auxiliary seat shown also in dotted lines in Figure 2 is designated by the numeral 93.

Since the entire navigation and control of the aircraft is de endent solel upon the uniform or difierential control 0 the two rotors 16 and 17, the aircraft of this novel construe tion does not require any auxiliary controls, sduch as ailerons, or vertical or horizontal ruders.

At the tail end of the fuselage 15, a pair of fixed horizontal stabilizers 94 may be provided of suitable area. Likewise, a stationary or rigid vertical stabilizer 95 may also be provided at the tail end of the fuselage. These surfaces 94 and. 95, however, are not control surfaces.

The landing gear may be any landing gear of conventional construction such as the pneumatic-tired wheels 96. at the front of the fuselage, carried in suitable landin gear mechw nism such as t e lower braces and 98 pivotally connected to the fuselage at 99 and the up or brace 100 having suitable shock absor rs 101 intermediate the ends thereof and also suitably pivotally mounted to the fuselage as at 102. A tail skid 103 may likewise provided at the rear end of the fuselage.

It 8 told he observed that the foregoing Ull low

construction maybe varied without departing from the principles involved in my-mven- Thus, for instance, instead of dl-iiivotally supporting the blades 18 upon r a al arms 81and'32, said radial arms may either be replaced or augmented by relatively thm tension iwires extending taut between the piv- I to meet practical requirements, as by greatly increasing the ratio or the mochemical advantage between the rotors and the manual controls within the fuselage, so as to reduce to a practical degree the amount ct manual force necessary to operate the controls and to maintain them in any set position,

Likewise, if desired, in addition to increasingthe ratio of the gear trains, a modified form oi mechanism may likewise be employed, by means of which the controls be; come non-reversible so as to relieve the operator'not only of any encessive manual force in operating the controls but oil all ezdort in maintaining the controls in any set position. Thus, by the interposition of suitable we gears between the rotors and the manual controls in the fuselage a non-reversible efieet may be obtained in the operation of the contro s.

In Figures 1 arid 2, I have shown the source of power, to wit,--the engine 90, positioned in the uppermost part of the fuselage with its main shaft axis intersecting the axis oil the driving shaft 19 of the rotors, In practice it may be desirable to osition the engine in the front or in the owermost part or near the bottom of the fuselage.

I am aware that the invention may be embodied in other specific forms without dc partin from the spirit or essential attributes thereo and I therefore desire the present embodiments to be considered in all respects as illustrative and not restrictive,reference being had to the appended claims rather than to the foregoing description to indicate the sec e of the invention. 7

aving thus described my invention what I claim as new and desire to secure by Letters Patent, is y 1. In an aircraft, a fuselage, a rotor having its axis of rotation extending transversely of the direction of travel, said rotor comprising a pivotally mounted blade, means for oscillating the blade about its pivot between limiting angular positions less than 360 degrees apart, during each revolution of the rotor, means for varying the positions ofthe outer weapon angular limits' of blade oscillations inlthe orbit ofthe blade, and means for var the maximum angle of deflection ofthe blade in. its orbit about the axis of the rotor. -2.]In anaircraft, a fuselage, a rotor comrising a plurality of pivotally mounted blades ada ted-to travel in an orbit about an axis e'xten ing transversely of the direction of travel of the aircraft, means for auto matically oscillating about its pivot each of the blades in succession during each revolution of the'rotor, between two predetermined limiting angles, means for positioning the two limits of angular blade oscillation at any desired part of the orbit of the blades at the will of the operator, and means for varying the angle between the two limits of blade oscillation, also at the will of the operator.

3. In an aircraft, a fuselage, a rotor comprising a plurality of aerofoil blades rotatably mounted about an axis extending transversely of the direction of travel of the air craft, a normally stationary composite eccentric for automatically deflecting each of the blades between two generally opposed limits of angular deflection, during each revolution of'the rotor, and means for varying the direction as well as the magnitude oi? the effective eccentricity of the composite eccentrio at the will of the operatonthereby to vary both the positions of the two limits of angular blade deflection in the orbit of the blades and also to vary the angle between 4. In an aircraft, a fuselage, a rotor con prising a plurality of aerofoils arranged to rotate about an am's extending transversely of the normal direction of travel of the aircraft, a composite eccentric comprising a plurality of dependent eccentrics, means for independently varying the direction or angle of the eccentricity of each of the plurality of dependent eccentrics at the will of the operator, thereby to vary boththe direction and magnitude of the resultant effective eccentricity of the composite eccentric, and thereby till such two opposed limits of blade deflection.

to vary the gosition of the two op osed limits 7 of blade de ection in the orbit o the blades, and also to vary the angle between such limits of blade deflection. a a

5. In an aircraft, a fuselage, a rotor comprising a plurality of aerofoil blades adapted to revolve generally about an axis extendin transversely ofthe normal direction of trave of the aircraft, a normallyv stationary, composite eccentric, means intermediate said composite eccentric and each of said blades for angularly oscillatin each of said blades between two opposed an redetermined limiting positions during eac revolution ofthe rotor, said composite eccentric comprising a plurality of normally stationary and adjustable, dependent eccentrics, and means for independently varying the direction of the eccentricity of each of said dependentieccentries at the will of the operator, thereby to vary both the direction as well as the magnitude of the resultant eflfective eccentricity of the composite eccentric, at the will of the operator.

6. In an aircraft, a fuselage, a pair of opposed rotors, each including a plurality of aerofoil blades adapted to revolve generally about an axis extending transversely ofthe direction of travel of the aircraft, automatic means for angularly oscillating each of the blades of the rotors between two opposed limits during each revolution of said rotors, means for varying the positions of the two opposed limits of angular blade deflection in the orbit of the blades at the will of the operator, and means for varying the angle between the two limits of angular blade deflection at the will of the operator.

7. In an aircraft, a fuselage, a pair of opposed rotors, each including a plurality of aerofoil blades adapted to revolve generally about an axis extending transversely of the normal direction of travel of the aircraft, automatic means for angularly oscillating each of the blades of the rotors between two opposed limits during each revolution of said rotors, means for varying the positions of the two opposed limits of angular blade deflection in the orbit of the blades at the will of the operator, means for varying the angle between the two limits of angular blade deflection at the will of the operator, and means for effectin said variations in the two opposed rotors o the aircraft, either uniformly or differentially, also at the will of the operator.

8. In an aircraft, a fuselage, a pair of opposed rotors, each comprising a plurality of aerofoil blades adapted to revolve enerally about an axis extending transversely of the normal direction of the travel of the aircraft, a normally stationary, composite eccentric in each of said rotors, means intermediate the composite eccentricand each of the blades of the rotors for automatically oscillating each of the blades between two opposed limits of angular blade deflection during each revolution of the rotors, each of said composite eccentrics comprising a plurality of dependent eccentrics, and means for varying the direction of eccentricity of each of said dependent eccentrics comprising each of the composite eccentrics, either jointly or independently of each other at the will of the operator, thereby to vary either the direction or the magnitude of the resultant effective eccentricity of the composite eccentrics or to vary both the direction and the magnitude of the effective eccentricity of said composite eccentrics. v

9. In an aircraft, a. fuselage, a pair of opposed rotors, each com rising a plurality of aerofoil blades adapte to revolve generally about an axis extending transversely of the normal direction of the travel of the aircraft, a normally stationary, composite eccentric in each of said rotors, means intermediate the composite eccentric and each of the blades of the rotors for automatically oscillating each of the blades between two opposed limits of angular blade deflection during each revolution of the rotors, each of said composite eccentrics comprising a plurality of dependent eccentrics, means for varying the direction of eccentricity of each of said dependent eccentrics comprising each of the composite eccentrics, either jointly or independently of each other at the will .of the operator,'thcreby to vary either the direction or the magnitude of the resultant effective eccentricity of the composite eccentrics or to vary both the direction and the magnitude of the effective eccentricity of said composite eccentrics, and means for effecting such joint or independent variations of directions of eccentricities in each of the pair of opposed rotors, either uniformly or differentially, zit-the will of the operator.

10. In an aircraft, a fuselage, a rotor comprising a plurality of pivotally mounted aerofoil blades adapted to travel generally about a common axis and extending transversely of the normal direction of travel of the aircraft, a source of power for revolving said rotor, means for oscillating each of said blades in succession during each revolution of said rotor, manually operable means for varying said oscillations, and means intermediate said source of power and said rotor for operatively connecting or disengaging the two, at the will of the operator.

11. In an aircraft, a fuselage, a driving shaft, a rotor carried by said driving shaft comprising a plurality of blades, means intermediate said driving shaft and each of said blades, rigidly secured to the former and having pivotal supporting connection with the latter, a stationary supporting frame, an eccentric carried by said stationary frame member, means intermediate said eccentric and each of said blades, having pivotal connection with the latter, manual controls within the fuselage, and means intermediate said manual controls and said eccentric for varying the direction and the magnitude of the eccentricity thereof, at the will of the operator.

12. In an aircraft, a fuselage, a driving shaft, a rotor carried by said driving shaft comprising a plurality of'blades, means intermediate said driving shaft and each of said blades, rigidly secured to the former and having pivotal supporting connection with the latter at substantially the center of gravity of the cross section thereof, a stationary supporting frame, an eccentric carried by said stationary frame member, means intermediate said eccentric and each of said blades, having pivotal connection with the latter,

.manual controls within the fuselage and means intermediate said manual controls and said eccentric for varying the direction and the magnitude ofthe eccentricity thereof, at the will of the operator.

- '13. In an aircraft, a fuselage, a driving shaft, a rotor carried b said driving shaft comprising a plurality 0 blades, means intermediate said driving shaft and each of said blades, rigidly secured to the former and having pivotal supporting connection with the latter, a stationary supporting frame, ,an eccentric carried by said stationary frame memblades, rigidly secured to the former and having pivotal supporting connection with the latter, at substantially the center of gravity of the cross section thereof, a stationary supporting frame, an eccentric carried by said stationary frame member, means intermediate said eccentric and each of said blades,

having pivotal connection with the latter, in advance of the pivotal supporting connection thereof, manual controls within the fuselage and means interm'ediatesaid manual controls and said eccentric for varying the direction and the magnitude of the eccentricity thereof, at the will of the operator.

15. In an aircraft, a fuselage, a driving shaft, a rotor carried by said driving shaft comprising a plurality of blades, means intermediate said driving shaft and each of said blades, rigidly secured to the former and having pivotal supporting connection with 17, An aircraft, comprising a fuselage a rotor, comprisin a plurality of pivotally mounted aerofoil lades, extending generally I transversely to the direction of travel of the aircraft and adafpted to revolve in an orbit about the axis 0 the rotor, means for automatically oscillating each of said aerofoil blades in succession about its respective pivot during each revolution of the rotor, and means for varying the magnitude of the oscillation and the event of the oscillation in the travel of the aerofoil blades about the axis of.

the rotor, at the will of the operator.

18. An aircraft comprising a fuselage, a rotor comprising a plurality of pivotally mounted aerofoil blades extending generally transversely to the direction of travel of the aircraft and adapted to revolve in an orbit about the axis of the rotor, a composite eccentric for oscillating each of said aerofoil blades in succession about its respective pivot, during each revolution of the rotor and for varying the magnitude and the event of sa1d oscillations, and manual control means for operating said composite eccentric to effect said variation of magnitude and event of the oscillations.

- HAVILAND H. PLATT.

the latter, a stationary supporting frame, a I

normally stationary eccentric earned by said stationary frame member, a second normally stationary eccentric carried by said first eccentric, Ineans intermediate said second eccentric and each of said blades, having pivotal connection with the latter, and means for independently rotating each of said eccentrics.

16. In an aircraft, a fuselage, a driving shaft, .a driving spider rigidly attached to said driving shaft, a plurality of blades pivot'ally mounted on said driving spider, a stationary supporting frame, a normally stationary eccentric carried by said supporting frame, a second normally stationary eccentric carried by said first eccentric, a connecting rod intermediate said second eccentric and each of said blades, and means for independ ently rotating each of said eccentrics. 

